It has been conventional practice in methods or processes of attenutating glass streams flowing from orifices in a stream feeder or bushing into fibers or filaments to utilize a bushing block of refractory disposed between the forehearth and the stream feeder or bushing. Such bushing blocks are generally a solid piece of refractory material and conventionally have a rectangle shaped opening or passing elongated lengthwise of the bushing through which glass from the forehearth flows.